Adapt field name in ValidationBindHandler to a valid ConfigurationPropertyName

Fixes gh-19580

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/bind/DataObjectPropertyName.java

@@ -21,9 +21,10 @@ package org.springframework.boot.context.properties.bind;
  *
  * @author Phillip Webb
  * @author Madhura Bhave
+ * @since 2.2.3
  * @see DataObjectBinder
  */
-abstract class DataObjectPropertyName {
+public abstract class DataObjectPropertyName {
 
 	private DataObjectPropertyName() {
 	}
@@ -33,7 +34,7 @@ abstract class DataObjectPropertyName {
 	 * @param name the source name
 	 * @return the dashed from
 	 */
-	static String toDashedForm(String name) {
+	public static String toDashedForm(String name) {
 		StringBuilder result = new StringBuilder();
 		String replaced = name.replace('_', '-');
 		for (int i = 0; i < replaced.length(); i++) {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/bind/validation/ValidationBindHandler.java

@@ -28,6 +28,7 @@ import org.springframework.boot.context.properties.bind.AbstractBindHandler;
 import org.springframework.boot.context.properties.bind.BindContext;
 import org.springframework.boot.context.properties.bind.BindHandler;
 import org.springframework.boot.context.properties.bind.Bindable;
+import org.springframework.boot.context.properties.bind.DataObjectPropertyName;
 import org.springframework.boot.context.properties.source.ConfigurationProperty;
 import org.springframework.boot.context.properties.source.ConfigurationPropertyName;
 import org.springframework.core.ResolvableType;
@@ -187,7 +188,7 @@ public class ValidationBindHandler extends AbstractBindHandler {
 		}
 
 		private ConfigurationPropertyName getName(String field) {
-			return this.name.append(field);
+			return this.name.append(DataObjectPropertyName.toDashedForm(field));
 		}
 
 		ValidationErrors getValidationErrors() {

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/context/properties/bind/validation/ValidationBindHandlerTests.java

@@ -193,6 +193,14 @@ class ValidationBindHandlerTests {
 				.satisfies((ex) -> assertThat(ex.getCause()).hasMessageContaining("years"));
 	}
 
+	@Test
+	void validationErrorsForCamelCaseFieldsShouldContainRejectedValue() {
+		this.sources.add(new MockConfigurationPropertySource("foo.inner.person-age", 2));
+		BindValidationException cause = bindAndExpectValidationError(() -> this.binder
+				.bind(ConfigurationPropertyName.of("foo"), Bindable.of(ExampleCamelCase.class), this.handler));
+		assertThat(cause.getMessage()).contains("rejected value [2]");
+	}
+
 	private BindValidationException bindAndExpectValidationError(Runnable action) {
 		try {
 			action.run();
@@ -305,6 +313,33 @@ class ValidationBindHandlerTests {
 
 	}
 
+	@Validated
+	static class ExampleCamelCase {
+
+		@Valid
+		private InnerProperties inner = new InnerProperties();
+
+		InnerProperties getInner() {
+			return this.inner;
+		}
+
+		static class InnerProperties {
+
+			@Min(5)
+			private int personAge;
+
+			int getPersonAge() {
+				return this.personAge;
+			}
+
+			void setPersonAge(int personAge) {
+				this.personAge = personAge;
+			}
+
+		}
+
+	}
+
 	@Validated
 	static class ExampleValidatedBeanWithGetterException {